Enzymes behave as biocatalysts, regulating many of the chemical reactions that naturally occur in living organisms. When isolated, enzymes also have many industrial, as well as medical uses. For instance, enzymes are used in the tanning industry and the detergent industry. Moreover, enzymes have many uses in the food industry, such as in the manufacture of cheese and alcoholic beverages.
In general, the traditional method in the production of enzymes has been to dissolve the enzyme in a water solution. Water, however, evaporates easily. Some enzymes, especially alkaline protease, are known to be potential health hazards to workers, and accordingly, it is desirable to keep them solubilized, i.e., prevent drying and/or dust formation. Dust and aerosols containing such enzymes can produce bronchial allergic reactions in sensitized persons. See, Flindt, "Pulmonary Disease Due to Inhalation of Derivatives of Bacillus Subtilis Containing Proteolytic Enzyme", The Lancet, from the Department of Occupational Health, University of Manchester, pages 1177-1184, (June 14, 1969). Moreover, enzymes such as alkaline protease (AP) easily precipitate out of a water solution. Thus, industrial production of such enzymes has been difficult due to their crystallization during the concentration steps employed in the traditional methods of production. These problems produced erratic yields and processing delays.
Thus, researchers had sought methods to keep enzymes, especially those that produce allergic reactions, dissolved in a closed system during processing. Nothing in the prior art, however teaches or suggests the use of a solvent other than water (or water with minor additives) to solubilize precipitated enzymes.
The prior art discloses that organic solvents, such as propylene glycol (PG), ethylene glycol (EG), and polyethylene glycol (PEG), may be employed during enzyme preparation. For instance, U.S. Pat. No. 4,497,897 discloses extraction of proteinase from Subtilisin Carlsberg using a solution of PG doped with carboxylate salt and calcium salt. U.S. Pat. No. 3,242,056 discloses a process employing aliphatic polyols in the preparation of lysozyme to promote heat stability in the lysozyme final product. U.S. Pat. No. 3,147,196 discloses a process in which tannin is added to an acidic enzyme-containing solution, and then the tannin-precipitated enzyme is extracted with an aqueous solution, which may contain PG or EG. However, tannin also ends up in the aqueous extract which is undesirable since tannin negatively interferes with the end use of the enzyme. Thus, additional processing is required so that the result is a solid, enzyme final product that is tannin-free. Also, U.S. Pat. No. 3,440,143 discloses extracting enzymes from plant tissue with an aqueous solution containing 0.5-5% of a high molecular weight PEG having at least 25 ethylene units to precipitate the phenols naturally present in plant tissue. None of the literature, however, suggests or discloses the present novel discovery of employing a novel solvent to prepare a solution of the enzyme.